Muslims have to stop eating and not swallow what is in their mouth.
What is the injunction of Shariah in a person who heard Fajr call for prayer while he was eating his Suhour? What should we do when hearing the call for prayer?
A Muslim has to stop eating and drinking when he hears the Muazzin’s call for Fajr prayer, and not swallow what is in his mouth. If he swallows anything deliberately after he hears the Takbeer for the Fajr prayer, then he invalidates his fast, and he has to abstain from eating and drinking and make up for that day, according to the majority of jurists.